Power conversion device

Abstract

To provide a power conversion device having a wider input voltage range.SOLUTION: A power conversion device includes: a plurality of converter sections transforming DC power input from a DC power supply; an inverter section converting DC power transformed by the converter sections into AC power and outputting the converted AC power; and a control section. The plurality of converter sections operate over different input voltage ranges, respectively, and the control section controls so as to supply DC power to an operable converter section based on the voltage of DC power input from the DC power supply.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] DC / AC inverters, which convert DC power to AC power, and DC / DC converters, which transform the voltage of DC power, are designed to operate normally within a specified input voltage range.General DC / AC inverters and DC / DC converters will not operate if an input voltage lower than the specified input voltage range is applied, and may be damaged if an input voltage higher than the specified input voltage range is applied. Summary of the Invention [Problem to be solved by the invention]

[0003] At least one object of the present invention is to provide a power converter having a wider input voltage range. [Means for solving the problem]

[0004] The object of the present invention is to [1] A power conversion device comprising: a plurality of converter units that transform DC power input from a DC power source; an inverter unit that converts the DC power transformed by the converter units into AC power and outputs the AC power; and a control unit, wherein the plurality of converter units operate within different input voltage ranges; and the control unit controls the supply of DC power to operable converter units based on the voltage of the DC power input from the DC power source; [2] The power conversion device according to [1], further comprising a power combining unit that combines the DC powers transformed by the converter units into one power, and the control unit is capable of controlling the DC power to be supplied to two or more converter units, and when DC powers are supplied to two or more converter units, the DC power combined by the power combining unit is supplied to the inverter unit; [3] The power conversion device according to [1] or [2], further comprising a plurality of switch circuits corresponding to the plurality of converter units, each of which is provided on the input side of the corresponding converter unit, and the control unit controls the switch circuit corresponding to the converter unit that supplies DC power so as to be conductive; [4] The power conversion device according to any one of [1] to [3] above, wherein the DC power source is a solar power generation device, a wind power generation device, a biological power generation device, a wave power generation device, and / or a fuel cell; This is achieved by: [Effects of the Invention]

[0005] According to the present invention, it is possible to provide a power conversion device having a wider input voltage range. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a block diagram showing a configuration of a power conversion device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments as long as they do not contradict the spirit of the present invention.

[0008] Fig. 1 is a block diagram showing the configuration of a power conversion device according to an embodiment of the present invention. The power conversion device 1 shown in Fig. 1 includes a control unit 11, three switch circuits 12 (12a to 12c), three converter units 13 (13a to 13c), a power combining unit 14, and an inverter unit 15.

[0009] The control unit 11, switch circuits 12 (12a to 12c), converter units 13 (13a to 13c), power combiner 14, and inverter unit 15 may be electrically connected by conductors or the like. In Fig. 1, gray solid lines indicate electrical connections. The power conversion device 1 may be electrically connected to a DC power source on the input side and electrically connected to a load or the like on the output side.

[0010] Furthermore, the control unit 11 and each of the switch circuits 12 (12a to 12c) may be connected via communication and / or electrically. The control unit 11 and each of the switch circuits 12 (12a to 12c) may be connected by wire or wirelessly. In Fig. 1, dashed arrows indicate the connection relationship between the control unit 11 and each of the switch circuits 12.

[0011] The converter unit 13 transforms the DC power. The converter unit 13 may be, for example, a DC / DC converter. The converter unit 13 may step up or step down the DC power.

[0012] The inverter unit 15 converts DC power into AC power.

[0013] 1, the power conversion device 1 includes three converter units 13, but the number of converter units 13 included in the power conversion device 1 is not particularly limited as long as it is two or more. The power conversion device 1 may include, for example, two or five converter units 13. It is preferable that the multiple converter units 13 included in the power conversion device 1 are connected in parallel.

[0014] 1, the power conversion device 1 includes three switch circuits 12, but the number of switch circuits 12 included in the power conversion device 1 is not particularly limited as long as it is two or more. The power conversion device 1 may include, for example, two or five switch circuits 12.

[0015] Preferably, the multiple switch circuits 12 included in the power conversion device 1 correspond to the multiple converter units 13, respectively. For example, one switch circuit 12 may be provided for one converter unit 13. Furthermore, the switch circuit 12 may be provided on the input side of the corresponding converter unit 13. In other words, the corresponding switch circuits 12 and converter units 13 may be connected in series, and the multiple switch circuits 12 may be connected in parallel. In FIG. 1, the switch circuit 12a corresponds to the converter unit 13a, the switch circuit 12b corresponds to the converter unit 13b, and the switch circuit 12c corresponds to the converter unit 13c.

[0016] When the switch circuit 12 is in the OFF state, the DC power supply and the converter unit 13 are disconnected, and power is not supplied to the converter unit 13 corresponding to the switch circuit 12. When the switch circuit 12 is turned ON and becomes conductive, power is supplied from the DC power supply to the converter unit 13 corresponding to the switch circuit 12.

[0017] The multiple converter units 13 included in the power conversion device 1 operate within different input voltage ranges. Note that "operate" refers to operating normally. The input voltage range within which the device operates normally may be, for example, an input voltage range determined by the manufacturer of the DC / DC converter. Hereinafter, the input voltage range within which the device operates normally is also referred to as the input voltage range.

[0018] The phrase "multiple converter units 13 operate within different input voltage ranges" means that the input voltage ranges of the multiple converter units 13 are different. The input voltage ranges of the multiple converter units 13 may overlap. Furthermore, some of the multiple converter units 13 may have the same input voltage range. For example, the input voltage range of converter unit 13a may be 6 to 12 V, the input voltage range of converter unit 13b may be 9 to 18 V, and the input voltage range of converter unit 13c may be 18 to 36 V.

[0019] When DC power is first input from the DC power source to the power conversion device 1, the multiple switch circuits 12 included in the power conversion device 1 may be turned off, and no power may be supplied to the converter unit 13. The DC power input from the DC power source to the power conversion device 1 may be supplied to the control unit 11, and the control unit 11 may measure the voltage of the DC power input to the power conversion device 1. The control unit 11 may include a circuit for measuring the voltage and a control circuit for controlling the switch circuits, which will be described later.

[0020] Based on the measured voltage, the control unit 11 controls so that DC power is supplied to the operable converter units 13. Specifically, for example, the control unit 11 may control so that power is supplied to the converter units 13 by turning on and conducting the switch circuits 12 corresponding to the converter units 13 having an input voltage range operable at the measured voltage.

[0021] The method by which the control unit 11 controls the switch circuit 12 to turn on is not particularly limited and can be designed as appropriate. For example, the control unit 11 may transmit a signal for driving the switch circuit 12 (hereinafter also referred to as a drive signal) to the switch circuit 12 to be turned on, thereby causing conduction. Hereinafter, it is assumed that the control unit 11 controls the switch circuit 12 to switch ON / OFF by transmitting the drive signal to the switch circuit 12.

[0022] If the power conversion device 1 does not include a converter unit 13 having an input voltage range that allows operation at the measured voltage, the control unit 11 may perform control so as not to supply DC power to any converter unit 13. For example, the control unit 11 does not need to send a drive signal to turn on any switch circuit 12.

[0023] Furthermore, when there are two or more converter units 13 having an input voltage range operable at the measured voltage, control may be performed to supply DC power to any one of the operable converter units 13, or to supply DC power to any two or more of the operable converter units 13, or to supply DC power to all of the operable converter units 13. In other words, control unit 11 may be capable of performing control to supply DC power to two or more converter units 13.

[0024] For example, in the case where converter units 13a to 13c have the input voltage range described above and control unit 11 controls so as to supply DC power to all of converter units 13 that are operable, when the voltage of the DC power input from the DC power source is 12V, control unit 11 may send a drive signal to switch circuit 12a and switch circuit 12b to turn them ON, and control so as to supply DC power to converter units 13a and 13b.

[0025] Even when the control unit 11 controls the supply of DC power to two or more converter units 13, the power combining unit 15 described later can combine the DC power transformed by the two or more converter units 13 into one power and supply it to the inverter unit 15.

[0026] The converter unit 13, which receives DC power, transforms and outputs the DC power input from the DC power source. The output voltage of the converter unit 13 is preferably a voltage included in the input voltage range of the inverter unit 15. The input voltage range of the inverter unit 15 may be, for example, an input voltage range determined by a company that manufactured the DC / AC converter. When the output voltages of the multiple converter units 13 are within the input voltage range of the inverter unit 15, the inverter unit 15 can operate normally using the power supplied from the multiple converter units 13. Furthermore, when DC power is supplied to two or more converter units 13, it is preferable that the output voltages of the two or more converter units 13 be the same voltage. Note that even if the output voltages of the two or more converter units 13 are not the same, the power combiner 15 can absorb the voltage difference, so the voltages do not need to be completely the same for operation.

[0027] The DC power transformed by the converter unit 13 is supplied to the power combining unit 14. When DC power is supplied to two or more converter units 13, the transformed DC power is supplied from the two or more converter units 13 to the power combining unit 14. The power combining unit 14 combines the powers supplied from the two or more converter units 13 into one power and supplies the power to the inverter unit 15. The multiple converter units 13 and the power combining unit 14 may be connected in series. The power combining unit 14 is not particularly limited as long as it can combine multiple DC powers into one DC power. Any configuration can be adopted for the power combining unit 14. When DC power is supplied to one converter unit 13, the DC power supplied from the one converter unit 13 to the power combining unit 14 is supplied to the inverter unit 15.

[0028] The DC power output from the power combining unit 14 is supplied to the inverter unit 15. The power combining unit 14 and the inverter unit 15 may be connected in series. The inverter unit 15 converts the supplied DC power into AC power and outputs it. The AC power output from the inverter unit 15 may be output from the power conversion device 1 and supplied to a load or the like electrically connected to the power conversion device 1.

[0029] The output voltage of the inverter unit 15 is not particularly limited and can be designed appropriately. The output voltage of the inverter unit 15 may be, for example, single-phase 100V, single-phase two-wire 100V, single-phase 200V, or three-phase 200V.

[0030] With this configuration, the power conversion device 1 can accommodate a wider range of input voltages than the input voltage range specified for the inverter unit 15. Furthermore, while DC power is being input from the DC power supply, the control unit 11 can measure the voltage of the input DC power and control the switch circuit 12 in real time. Therefore, if the voltage of the DC power being input from the DC power supply fluctuates midway, the control unit 11 can control the supply of DC power to the converter unit 13 that can operate at the fluctuated voltage.

[0031] For example, in a case where converter units 13a to 13c have the input voltage range described above and control unit 11 controls so as to supply DC power to all of converter units 13 that are operable, when the voltage of the DC power input from the DC power supply continuously fluctuates from 12 V to 18 V, control unit 11 may control so as to change converter units 13 that supply DC power from converter units 13a and 13b to only converter unit 13b, and then to converter units 13b and 13c. For example, control unit 11 may control so as to cut off the power supply to converter unit 13a by sending a drive signal to switch circuit 12a to turn it OFF when the voltage of the DC power input from the DC power supply becomes greater than 12 V. Furthermore, for example, control unit 11 may control so as to turn on switch circuit 12c to conduct power to converter unit 13c when the voltage of the DC power input from the DC power supply becomes 18 V.

[0032] The DC power source that inputs DC power to the power conversion device 1 may be, for example, a solar power generation device, a wind power generation device, a biological power generation device, a wave power generation device, a fuel cell, or the like. In these power generation methods using DC power sources, the voltage of the generated power fluctuates depending on the environment and situation, but the power conversion device 1 can operate normally even when power with a fluctuating voltage is input. Note that if the DC power source is one that generates AC power, such as wind power generation, the DC power can be converted to DC power before being input to the power conversion device 1.

[0033] The power conversion device 1 can also be connected to a DC power supply other than those mentioned above. For example, the DC power supply may be a lithium ion battery, a lead storage battery, a cell stack, or the like.

[0034] Although the above description has been given of an example in which the control unit 11 includes a circuit for measuring voltage and a control circuit for controlling the switch circuit, the power conversion device may also include a voltage measurement unit for measuring voltage and a control unit for controlling the switch circuit. In this case, the voltage measurement unit may measure the voltage of DC power input from the DC power supply and transmit the measured voltage to the control unit.

[0035] Furthermore, in the above, the power conversion device 1 has been described as having a control unit 11, a switch circuit 12, a converter unit 13, a power combining unit 14, and an inverter unit 15, but the power conversion device may have any configuration other than the control unit, switch circuit, converter unit, power combining unit, and inverter unit.

[0036] In this way, the power conversion device comprises a plurality of converter units that transform DC power input from a DC power source, an inverter unit that converts the DC power transformed by the converter units into AC power and outputs it, and a control unit, and the plurality of converter units each operate within a different input voltage range, and the control unit controls the supply of DC power to operable converter units based on the voltage of the DC power input from the DC power source, thereby making it possible to provide a power conversion device with a wider input voltage range.

[0037] The power conversion device has a wide input voltage range, so that it can be connected to a DC power source with a non-constant output voltage and convert power, as described above. Also, even in a situation where only limited equipment is available, such as during a disaster, it can be connected to DC power sources with various output voltages and convert power.

[0038] Furthermore, while a typical DC / DC converter will be damaged if a voltage exceeding the input voltage range is applied, the power conversion device of the present invention does not apply a voltage outside the input voltage range to the converter section, thereby avoiding the risk of damage.

[0039] Furthermore, in this way, the power conversion device is provided with a power combining unit that combines the DC power transformed by the converter units into one power, and the control unit is capable of controlling the supply of DC power to two or more converter units.When DC power is supplied to two or more converter units, the DC power combined by the power combining unit is supplied to the inverter unit, thereby making it possible to prevent interruption of the power output from the power conversion device even when the voltage of the DC power input from the DC power source fluctuates.

[0040] Furthermore, in this way, the power conversion device includes a plurality of switch circuits corresponding to each of the plurality of converter units, and the switch circuits are provided on the input side of the corresponding converter units, and the control unit controls the switch circuit corresponding to the converter unit that supplies DC power to be conductive, thereby making it possible to switch the converter unit that supplies DC power using the switch circuit.

[0041] Furthermore, by using a DC power source such as a solar power generation device, a wind power generation device, a biological power generation device, a wave power generation device, and / or a fuel cell, it is possible to convert the power generated by a DC power source whose voltage fluctuates depending on the environment and situation. [Explanation of symbols]

[0042] 1 Power conversion device 11 Control section 12 Switch Circuit 13 Converter section 14 Power combiner 15 Inverter section

Claims

1. a plurality of converter units that transform DC power input from a DC power supply; an inverter unit that converts the DC power transformed by the converter unit into AC power and outputs the AC power; a control unit; The plurality of converter units each operate within a different input voltage range, the control unit controls the supply of DC power to the operable converter unit based on the voltage of DC power input from the DC power source; Power conversion device.

2. A power combining section that combines the DC power transformed by the converter section into one power. Equipped with The control unit is capable of controlling the supply of DC power to two or more converter units, When DC power is supplied to two or more converter units, the DC power combined by the power combining unit is supplied to the inverter unit. The power conversion device according to claim 1 .

3. A plurality of switch circuits corresponding to the plurality of converter units Equipped with A switch circuit is provided on the input side of the corresponding converter unit, The control unit controls the switch circuit corresponding to the converter unit that supplies DC power so as to be conductive. The power conversion device according to claim 1 or 2.

4. The DC power source is a solar power generator, a wind power generator, a biopower generator, a wave power generator, and / or a fuel cell. The power conversion device according to claim 1 or 2.

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